Two women involved in running a “careful and professional” cannabis growing operation in Outwell at first thought it was a joke when police carried out a raid, a court heard.

Lauren Brazier, 33, and Charlotte Sieley, 30, were found in a locked unit with eight mature cannabis plants when police raided the farm at Langhorn’s Lane.

When officers searched other outbuildings at the site they found more cannabis plants in various stages of growth, and the well-organised operation was said to have the potential of producing cannabis, with a street value of more than £120,000, Norwich Crown Court heard.

Richard Kelly, prosecuting, said that the set-up meant the plants were divided into different growing stages in a “conveyor belt” system and said: “It was a careful and professional operation.”

He said the unit where the two women were found during the police raid was an area used for harvesting and drying the cannabis.

“On the day of the raid both defendants were together in a small unit.”

He said the unit was locked and when police asked them to open up they thought at first it was someone “mucking about” before realising it was in fact a police raid taking place.

Brazier of The Drove, Downham Market, and Sieley of The Poplars, Elm, both admitted production of cannabis but had claimed they were only involved in growing the eight plants they were found with in the unit and claimed it was for their own personal use. They also claimed they had no idea about the other units on the site being used to grow cannabis.

However Judge Andrew Shaw rejected their claim at the hearing and ruled that they had been part of a professional set-up and not just growing the cannabis for their own use.

He said: “This was a conveyor belt operation.”

Judge Shaw adjourned sentence until November 16 and ordered reports but told them: “You have both pleaded guilty to a serious offence. Normally people involved in this sort of offending get custody.”

Guy Williamson, for Brazier, and Jamil Mohammed for Sieley.

The two woman are due to be sentenced with a third defendant, who has admitted allowing premises to be used for growing cannabis.